THIS AVALANCHE ADVISORY EXPIRED ON January 14, 2017 @ 6:50 am
Avalanche Advisory published on January 13, 2017 @ 6:50 am
Issued by Steve Reynaud - Tahoe National Forest

Moderate avalanche danger exists throughout the forecast area at all elevations due to wind slab and deep slab avalanche problems.  Human triggered avalanches remain possible today.  Evaluate snow and terrain carefully, identify features of concern. 

2. Moderate

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Above Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Near Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Wind Slab
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Strong NE/E winds will be able to transport snow today and form winds slabs on SE-S-SW-W-NW aspects near and above treeline.  The low density storm snow that fell yesterday will be easily transported with the strong NE/E winds.  Pay attention to top wind loading and cross wind loading of terrain features.  Look for blowing snow, new cornice formation, and wind pillows to help identify where wind slabs are developing.  Large cornices continue to exist along ridgelines, extra caution is advised around these hazards.

Avalanche Problem 2: Deep Slab
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Deep slab avalanches are becoming unlikely as our recent storm snow continues to settle and gain strength, and the snow below the Jan 9 rain crust begins to refreeze.  These deep slab avalanches are characterized by failure more than 3 feet deep in the snowpack and could be large wind slabs, storm slabs, or failures deeper in the snowpack to the Jan 9 or Dec. 15 rain crusts.  A widespread natural deep slab avalanche cycle occurred during the past storm cycle with many slopes avalanching.  No avalanches are thought to have happened with this avalanche problem since the main storm ended on Wednesday.  Large triggers in isolated areas remain the concern for today.   

 

recent observations

Observations were received from Powderhouse (Luther Pass area), Wildflower Ridge (Donner Summit area), Deep Creek (Cabin Creek area), and Horse Meadows (Luther Pass area).  All areas received 4 to 8'' of additional snow yesterday.  Very little wind was reported with no wind slab development throughout the day with this new storm snow.  All areas reported signs of the previous storm snow settling, gaining strength, with formal and informal observations showing little to no signs of instabilities.  Many reports coming in of past avalanche activity throughout the forecast area from during or immediately after the storm cycle.  All of these avalanches are thought to have occurred sometime Wednesday or before.   

Weather and CURRENT CONDITIONS
weather summary

This weekend should bring us quieter and colder weather than we have seen in awhile.  High pressure builds into the region with some scattered sky coverage and highs mostly below freezing.  Sunday has a slight chance of a slider type system bringing some snow to our area.  By later next week, we could return to a wet and active weather pattern. 

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 20 to 21 deg. F.
Max. temperature in the last 24 hours: 27 deg. F.
Average wind direction during the last 24 hours: NE/E
Average wind speed during the last 24 hours: 25 to 30 mph
Maximum wind gust in the last 24 hours: 54 mph
New snowfall in the last 24 hours: 3 to 8 inches
Total snow depth: 89 to 113 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Friday Friday Night Saturday
Weather: Cloudy then becoming mostly cloudy. Scattered snow showers in the morning becoming isolated snow showers in the afternoon. Partly cloudy. Mostly cloudy.
Temperatures: 24 to 29 deg. F. 10 to 18 deg. F. 29 to 34 deg. F.
Wind Direction:
Wind Speed: Calm winds. Calm winds. Gusts up to 25mph in the evening. Light winds.
Expected snowfall: Trace in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Friday Friday Night Saturday
Weather: Cloudy then becoming mostly cloudy. Scattered snow showers in the morning then isolated snow showers in the afternoon. Partly cloudy. Mostly cloudy.
Temperatures: 22 to 27 deg. F. 13 to 19 deg. F. 29 to 34 deg. F.
Wind Direction: E E
Wind Speed: 15 to 20mph with gusts to 45mph. 10 to 15mph with gusts to 35mph. Light winds. Gusts up to 25mph in the afternoon.
Expected snowfall: Trace in. 0 in. 0 in.
Disclaimer

This avalanche advisory is provided through a partnership between the Tahoe National Forest and the Sierra Avalanche Center. This advisory covers the Central Sierra Nevada Mountains between Yuba Pass on the north and Ebbetts Pass on the south. Click here for a map of the forecast area. This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

For a recorded version of the Avalanche Advisory call (530) 587-3558 x258